Devices for collecting chemical compounds

ABSTRACT

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agent, chemical attribution signatures and toxic industrial chemicals.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of co-pending U.S.patent application Ser. No. 12/777,951 to Scott et al., filed on May 11,2010, the disclosure of which application is incorporated by referenceherein in its entirety.

GOVERNMENT RIGHTS

This invention was made with government support under Contract No.DE-AC07-05ID14517 awarded by the United States Department of Energy. Thegovernment has certain rights in the invention.

TECHNICAL FIELD

The present disclosure relates to devices and methods for collectingchemical compounds. More specifically, embodiments of the presentdisclosure relate to a portable extraction device for collecting andtransporting chemical compounds for analysis and related methods.

BACKGROUND

In a release of toxic chemicals into an urban or indoor environment, awide range of compounds will be dispersed in addition to the principaltoxin. These compounds, often referred to as “chemical attributionsignature” (CAS) compounds, are derived from the synthesis anddegradation of the toxin mixture, thus, they are highly indicative ofthe synthetic route, stabilization, storage, and methods of release. CAScompounds may have significant forensic value, provided they may beeffectively collected at the event site.

For example, during the release of a chemical warfare agent (CWA) as anact of terrorism, there is a potential for a significant number ofcasualties from exposure to one or more toxins in the CWA. Suchcasualties may occur by inhalation or by dermal contact with aerosols orcontaminated surfaces. In the aftermath of a CWA release, treatment ofthe victims, and decontamination and re-entry of the affected area willbe high recovery priorities. Another activity of high priority will befast and accurate identification of the perpetrators.

The identification of the CWA is the first and most important objective,since this dictates treatment of the victims and provides guidance forthe amount of time an affected area will remain toxic due to residualagent. CWA identification is expected to be straightforward becauseanalytical approaches are well developed. However, identification of theagent alone is not likely to provide substantial forensic information. Amore detailed analysis having greater forensic value may be gained byidentifying synthetic byproduct compounds that may be present in theagent. Synthetic byproduct compounds are indicative of a synthetic routethat was used to synthesize the CWA, and may also contain information onhow the agent was stored, stabilized, and released. Because thesynthetic byproducts present in the CWAs are unique to synthetic routesused in their formation, these compounds may be used as CAS compounds.

The characterization of CAS compounds on fixed surfaces may beanalytically challenging for several reasons. The chemical background inan anthropogenic environment includes a large number of compounds thatmay be present in high concentrations. For example, virtually anypolymeric material will contain a large quantity of plasticizers andsolvents, which will produce analytical responses that may bedistinguished from those of the CAS compounds. The CAS compounds thatare of highest value for identifying synthetic approaches willfrequently be present at trace concentrations. These compounds are notformed intentionally, and their concentrations may have been reduced bypurification steps used in synthesis. The concentrations of some of thetoxins and the CAS compounds may decrease quickly after release, onaccount of volatilization and loss to the atmosphere, diffusion into abulk solid, and/or degradation reactions. The CAS compounds may undergodegradation by hydrolysis, photolysis, oxidation, or condensation withother compounds in the chemical environment. Hydrolysis and oxidationreactions may be enhanced by treatment with decontamination solutionsduring recovery efforts. These degradation reactions may result inchanges to the chemical nature of the CAS compounds that drives the needfor effective sampling of exposed surfaces.

A method of analyzing organic compounds, such as phosphoryl compounds,sulfide compounds, and amine compounds, may be performed without samplepreparation by bombarding surfaces with energetic molecules. Morespecifically, surface-adsorbed compounds are sputtered into the gasphase where they may be detected using mass spectrometry (MS). Thedrawback to this method is that it requires acquisition of a sample ofthe solid surface.

More recently, new approaches have emerged that enable directinterrogation of surfaces using a mass spectrometer. One such approachis desorption electrospray ionization (DESI) mass spectrometry, whichutilizes energetic droplets to impact contaminated surfaces. Thedroplets pick up surface contaminants that are then analyzed, and thetechnique has recently been demonstrated for analysis of chemicalwarfare agents. Another approach, referred to as “direct analysis inreal time” (DART), utilizes an energetic noble gas plasma to removesurface contaminants that are then analyzed using mass spectrometry.Although these techniques enable on-site analysis, they are expensive,difficult to transport, and hence are not viable options for most lawenforcement organizations.

CWA and associated CAS compounds may contact multiple fixed surfaces,and cannot be readily sampled using conventional approaches involvingremoval and transport to a forensic laboratory for analysis. There is aneed for facile, rapid collection of samples containing chemical warfareagent (CWA) attribution signatures after a CWA release.

BRIEF SUMMARY

Embodiments of the present disclosure include portable vacuum extractiondevices. In some embodiments, the portable vacuum extraction device mayinclude a plunger slidably inserted from one end of a chamber and havingan aperture therethrough, the plunger fitted within the chamber suchthat retraction thereof results in a decrease in pressure within thechamber, a seal structure for preventing air from entering the chamberupon retraction of the plunger and at least one pressure sensor fordetermining a pressure within the chamber. The device may furtherinclude a sorbent material sized and configured to be inserted throughthe aperture in the plunger.

Another embodiment of the portable vacuum extraction device may includea plunger slidably inserted from one end of a chamber and having anaperture therethrough, the plunger fitted within the chamber such thatretraction thereof results in a decrease in pressure within the chamber,a sorbent material sized and configured to be inserted through theaperture in the plunger, a seal structure for preventing air fromentering the chamber upon retraction of the plunger and at one leastactuation device attached to the plunger and configured for removing theplunger from the chamber.

Yet another embodiment of the portable vacuum extraction device mayinclude a plunger slidably inserted from one end of a chamber and havingan aperture therethrough, the plunger fitted within the chamber, asorbent material sized and configured to be inserted through theaperture in the plunger, a seal structure for preventing air fromentering the chamber upon retraction of the plunger and at least oneheating element configured for heating the chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming that which is regarded as the presentdisclosure, advantages of this disclosure may be more readilyascertained from the following detailed description when read inconjunction with the accompanying drawings in which:

FIG. 1 is an illustration of a portable vacuum extraction deviceaccording to an embodiment of the present disclosure.

FIG. 2 is an illustration of a portable vacuum extraction deviceaccording to another embodiment of the present disclosure.

FIG. 3 is an illustration of a portable vacuum extraction deviceaccording to another embodiment of the present disclosure.

FIGS. 4A through 4H2 illustrate a portable vacuum extraction deviceaccording to another embodiment of the present disclosure and illustratea method of collecting one or more chemical compound(s) according to anembodiment of the present disclosure.

FIGS. 5A and 5B are schematic illustrations of a portable vacuumextraction during collection of a chemical compound according to thepresent disclosure and corresponding gas chromatographic (GC) profilesdemonstrating the efficiency of chemical compound collected and show adetection comparison of collection at atmospheric pressure and undervacuum pressure.

FIGS. 6A through 6C are chromatograms obtained from a solid-phasemicroextraction (SPME) fiber exposed to triethyl phosphate using adevice according to an embodiment of the present disclosure.

FIG. 6D is a plot illustrating collection of TBP according to anembodiment of the present disclosure with increasing sampling time.

FIG. 7A through 7C are gas chromatograms obtained during collection ofDIMP comparing different SPME fibers, according to an embodiment of thepresent disclosure (metal body FVE). SPME fiber composition: FIG. 7A, 7μm polydimethyl-siloxane; FIG. 7B, 65 μmpolydimethyl-siloxane-divinylbenzene, and FIG. 7C, 85 μmcarboxen-polydimethylsiloxane.

FIGS. 8A through 8C are TD/GC/MS profiles of diethylphosphite (DEPt)eluting from the GC at about 13.4 min, collected from glass using adevice (metal body) according to an embodiment of the presentdisclosure.

FIG. 9 is a mass spectrum of DEPt collected from glass at a RT of about13.4 minutes using a device (metal body) according to an embodiment ofthe present disclosure.

FIG. 10 is a schematic diagram of the mass spectrometric fragmentationof DEPt collected using a device according to an embodiment of thepresent disclosure (metal body).

FIGS. 11A through 11C are TD/GC/MS profiles of triethyl phosphate (TEP)collected from glass using a device according to an embodiment of thepresent disclosure (metal body).

FIG. 12 is a mass spectrum of TEP at a RT of about 10.9 minutes obtainedfrom a sample collected from glass using a device according to anembodiment of the present disclosure (metal body).

FIG. 13 is a schematic diagram of the mass spectrometric fragmentationof TEP collected from glass using a device according to an embodiment ofthe present disclosure (metal body).

FIG. 14 is a mass spectrum of compound eluting at a RT of about 5.3minutes obtained from a sample collected from glass from a glass surfaceexposed to TEP using a device according to an embodiment of the presentdisclosure (metal body).

FIG. 15 is a schematic diagram of the mass spectrometric fragmentationfor dimethylphosphite (DMPt) collected from glass using a deviceaccording to an embodiment of the present disclosure (metal body).

FIG. 16 is a mass spectrum of compound eluting at a RT of about 6.65minutes obtained from a sample collected from glass using a deviceaccording to an embodiment of the present disclosure (metal body).

FIG. 17 is a schematic diagram of the mass spectrometric fragmentationfor ethyl methyl phosphite (EMPt) collected from glass using a deviceaccording to an embodiment of the present disclosure (metal body).

FIG. 18 is a mass spectrum of the compound eluting at a RT of about 8.05minutes, probably diethyl phosphite (DEPt), obtained from a sample fromglass collected using a device according to an embodiment of the presentdisclosure (metal body).

FIG. 19 is an illustration of hydrolysis of 2-S (diisopropylaminoethyl)O-ethyl methylphosphonothiolate (VX) that produces ethylmethylphosphonic acid (EMPA) and diisopropylaminoethanethiol (DESH),which were recovered using a device according to an embodiment of thepresent disclosure (metal body).

FIGS. 20A through 20C are TD/GC/MS profiles of compounds collected fromglass exposed to a solution of ethyl methylphosphonic acid (EMPA).Samples were acquired using a device according to an embodiment of thepresent disclosure (metal body).

FIG. 21 is a mass spectrum of DEMP, which was recovered using a deviceaccording to an embodiment of the present disclosure, eluting at a RT ofabout 17 minutes shown in FIGS. 20A through 20C.

FIG. 22 is a schematic mass spectrometric fragmentation for DEMP.

FIGS. 23A through 23C is TD/GC/MS profiles of tributyl phosphate (TBP)collected from a glass surface using a device according to an embodimentof the present disclosure (metal body).

FIG. 24 is a mass spectrum of TBP collected from glass exposed to TBPusing a device according to an embodiment of the present disclosure(metal body).

FIG. 25 is a schematic diagram of the mass spectrometric fragmentationof TPB.

FIG. 26 is a mass spectrum of a TBP-derived compound collected fromglass exposed to TBP using a device according to an embodiment of thepresent disclosure (metal body).

FIGS. 27A through 27C are TD/GC/MS profiles of DMMP collected frompainted wallboard using a device according to an embodiment of thepresent disclosure (metal body).

FIG. 28 is a mass spectrum of DMMP, which was recovered using a deviceaccording to an embodiment of the present disclosure, acquired from thepeak of FIGS. 27A through 27C eluting at a RT of about 7.8 minutes.

FIG. 29 is the schematic diagram of the mass spectrometric fragmentationfor DMMP.

FIGS. 30A through 30C are a collection of TD/GC/MS profiles of DESHhydrochloride collected from glass using a device according to anembodiment of the present disclosure (metal body).

FIG. 31 is a mass spectrum of DESH, which was recovered using a deviceaccording to an embodiment of the present disclosure, eluting at a RT ofabout 27.1 minutes as shown in FIG. 30B.

FIG. 32 is a schematic diagram for the formation of m/z 114 and m/z 72shown in FIG. 31 by fragmentation of the DESH radical cation.

FIG. 33 is a mass spectrum of a DESH-derived compound, which wasrecovered using a device according to an embodiment of the presentdisclosure, eluting at a RT of about 27.5 minutes as shown in FIG. 30C.

FIG. 34 shows a schematic diagram for the formation of ions at m/z 86and m/z 44 from slow-eluting compounds related to DESH.

FIGS. 35A through 35C show TD/GC/MS profiles of CEES, surrogate formustard gas, collected from glass using a device according to anembodiment of the present disclosure (plastic syringe body).

FIG. 36 shows mass spectra of CEES and methoxyethyl ethyl sulfide(MeOEES), which were recovered using a device according to an embodimentof the present disclosure, eluting at retention times of about 7.3minutes and 7.0 minutes shown in FIGS. 35A through 35C.

FIG. 37 shows TD/GC/MS profiles of an alkyl phosphite mixture collectedfrom glass using a device according to an embodiment of the presentdisclosure (plastic syringe body).

FIG. 38 shows a mass spectrum of DMPt, and DEPt, which were recoveredusing a device according to an embodiment of the present disclosure andwhich correspond to the peaks shown in FIG. 37.

FIG. 39 shows TD/GC/MS profiles of diisopropylaminoethanol (DIPAE)collected from a glass surface using a device according to an embodimentof the present disclosure (plastic syringe body).

FIG. 40 shows a mass spectrum of DIPAE, which was recovered using adevice according to an embodiment of the present disclosure, acquiredfrom the peak shown in FIG. 39.

FIG. 41 shows TD/GC/MS profiles of compounds collected from a surfaceexposed to a solution of ethyl dichlorothiophosphate using a deviceaccording to an embodiment of the present disclosure (plastic syringebody).

FIG. 42 shows a mass spectrum of compounds collected from a surfaceexposed to a solution of ethyl dichlorothiophosphate using a deviceaccording to an embodiment of the present disclosure (plastic syringebody), which were acquired from the peak shown in FIG. 41.

FIG. 43 is chromatographic trace produced by GC/MS analysis of an SPMEsample exposed during sampling of a wallboard surface exposed to aphosphate-phosphite mixture using a device according to an embodiment ofthe present disclosure (plastic syringe body).

FIG. 44 is chromatogram of a sample pulled from glass exposed to diethylphosphite using a device according to an embodiment of the presentdisclosure (plastic syringe body).

FIG. 45 is a chromatogram of a sample pulled from glass exposed toethyldichorothiophosphate using a device according to an embodiment ofthe present disclosure (plastic syringe body).

FIGS. 46 through 72 are TD/GC/MS chromatograms and mass spectra ofsamples obtained from glass or painted wallboard exposed to chemicalcompounds using a device according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

A portable extraction device and methods of performing extraction aredisclosed. In some embodiments, the portable extraction device includesa chamber fitted with a plunger and an absorptive fiber. The portableextraction device may be placed in contact with a surface to be sampledand a pressure within the chamber may be reduced by retracting theplunger. In other embodiments, the portable extraction device may beplaced over an area to be sampled and a pressure within the chamber maybe reduced using a vacuum pump, which increases rates of volatilizationof one or more chemical compounds, such as toxic industrial chemicals(TICs), semi-volatile organic or organometallic compounds, or otherchemicals of interest. The term “target compound,” as used herein, meansand includes any chemical compound(s) of interest. A fraction of thevolatilized target compounds may be partitioned into the absorptivefiber, which may then be analyzed using any number of methods. Forexample, the sample may be analyzed at a laboratory using a detectionmethod, such as, thermal desorption (TD), gas chromatography (GC) and/ormass spectrometry (MS). As another example, the sample may be analyzedby thermal desorption into an ion mobility spectrometer (IMS) that may,optionally, be coupled to an MS. The portable extraction device enablesefficient and cost-effective collection of multiple samples compatiblewith automated instrumentation and detection methods currently utilizedin forensic laboratories. For example, the portable extractor device maybe used to quickly collect multiple samples from fixed surfaces afterexposure to the target compounds.

Since the target compounds may have limited volatility, they mayoverwhelmingly partition onto or in fixed surfaces of a releaseenvironment and may, thus, be inefficiently sampled in the ambient air.In addition, the target compounds tend to be lipophilic and have asignificant dipole moment, which are properties that result in strongsurface adsorption or absorption into bulk materials. Thus, they may notbe easily detected by direct surface sampling or the use of swipes thatare then analyzed. The portable extraction device includes a vacuum toenhance a rate of volatilization of the target compounds and, thus,improves collection. As used herein, the term “vacuum” means andincludes a pressure below atmospheric pressure and is expressed withrespect to zero pressure (or absolute mode) and not with respect toambient pressure or some other pressure. It is noted that atmosphericpressure is nominally 1×10⁵ Pa (Pascal) in absolute mode. It isappreciated by a person of ordinary skill in the art that the degree ofvacuum may be pressures in a range between about 10⁵ and about 10⁻¹⁰ Pa,but preferably in a range between about 10⁵ and about 10⁻⁷ Pa, and morepreferably in a range between about 10⁵ to about 10⁻⁴ Pa. It isappreciated by a person of ordinary skill in the art that the vacuum maybe produced by any conventional vacuum generating equipment.

Many chemical compounds, such as those in chemical warfare agents (CWAs)absorb into or adsorb onto surrounding materials. For example, when theCWA surrogate compounds were applied to polymeric materials, asignificant fraction diffused into the polymeric material and could notbe detected either on the surface or in the headspace. However, whenthese samples were analyzed using vacuum extraction mass spectrometry,the direction of diffusion was reversed, and the compounds werevolatilized and detected. These studies demonstrated the utility of avacuum for increasing rates of volatilization over an absorptivesurface, and suggested that a vacuum extraction approach might be highlyeffective for a portable device to collect CWAs and/or target compoundsfrom fixed surfaces.

While inexpensive, handheld devices according to embodiments of thedisclosure may be used for forensics at chemical warfare agent releaseevents, these devices and related methods are useful for detecting anychemicals (industrial, drugs, explosives, etc.) that have been exposedto surfaces, and especially useful for those chemicals with lower vaporpressures. Thus, while the devices may be useful for law enforcementtype laboratories (CSI types for state and FBI as well as DHS), thedevices may also be useful for the EPA and other agencies that need todetect chemicals from surfaces. These devices may also be useful forprivate environmental consulting firms that may need to determine ifcontamination exists at a site, or if remediation strategies have beensuccessful.

While not wishing to be bound by a particular theory, application of amodest vacuum to a contaminated surface may increase rates ofvolatilization of compounds, such as target compounds, providingefficient, sensitive and cost-effective sampling approaches. Increasedvolatilization rates may be exploited by coupling a vacuum with anabsorptive fiber for capturing volatilized compounds. Use of a sorbentmaterial, such as solid-phase microextraction (SPME) fibers, may be usedfor capturing vapors in a modest vacuum environment. As used herein, theterm “sorbent material” means and includes a material that sorbs anothersubstance and that has the capacity or tendency to take up the substanceby either absorption or adsorption. The sorbent material provides asampling medium compatible with thermal desorption/gaschromatography/mass spectrometry (TD/GC/MS) instrumentation found inmost forensic laboratories. The term “TD/GC/MS,” as used herein, meansand includes thermal desorption (TD) coupled with gaschromatography-mass spectrometry (GC-MS). The combination of a modestvacuum, vacuum extractor, high efficiency SPME fibers, and TD/GC/MSanalysis will provide a methodology for effective sampling and analysisfor target compounds collected from fixed surfaces. While TD/GC/MS iscurrently one of the most common analytical tools available, analysis ofthe sample collected on the SPME material is not limited to thistechnique.

The portable extraction device of embodiments of the present disclosuretakes advantage of increased rates of volatilization at reducedpressures. Current studies show that configuration of the portableextraction device in a static mode results in diffusion of absorbedcompounds to the surface, and subsequent volatilization. A fraction ofthe vapors that are generated are captured by absorbent fibers, whichare then analyzed using TD/GC/MS.

Collection and identification of the target compounds may posesubstantial problems, because they are likely to be inhomogeneouslydistributed on fixed surfaces that frequently cannot be removed fortransport to a forensic laboratory (e.g., walls, windows, etc.). Thetarget compounds will likely be present in low concentrations in anenvironment that contains high concentrations of background chemicals,and they may be depleted by degradation reactions, volatilization, ordiffusion into solid bulk matrices. The device enables rapid andefficient collection of multiple samples of target compounds from fixedsurfaces, in order to accurately characterize and attribute origins ofreleased CWA.

In some embodiments, the portable vacuum extraction device may include asmall pre-evacuated chamber that is placed over the surface to besampled, a solid-phase microextraction fiber (SPME), and a valve.Opening the valve modestly reduces the pressure over the surface andincreases the rate of target compound volatilization. A fraction of thevolatilized target compounds partition into the fiber, which issubsequently analyzed using a thermal desorption/gas chromatography/massspectrometer, which is instrumentation common to many forensiclaboratories. Recovery of target compounds and related impurities wasdemonstrated from glass and paper surfaces, and the most recent studiesindicate efficacy for recovering target signatures from paintedwallboard.

Disclosed herein are several embodiments for a portable extractiondevice prototype. In some embodiments, the portable extraction deviceincludes a pump to provide the continuous vacuum during sampling and maybe referred to herein as a “dynamic portable vacuum extractor” (d-PVE).In another embodiment, the portable extraction device includes apre-evacuated chamber such that a pump is not necessary during thesampling process and may be referred to herein as a “static portablevacuum extractor” (s-PVE). In yet another embodiment, the portablevacuum extraction device may include dual chambers and a suction fan forcreating a modest vacuum and may be referred to herein as a “hybridportable vacuum extractor” (h-PVE). In yet another embodiment, theportable vacuum extraction device may include a syringe with a plungerto create the modest vacuum and may be referred to herein as a “fieldportable vacuum extractor” (f-PVE).

FIG. 1 is a simplified illustration of an embodiment of a portableextraction device 100 that may be used to collect samples of one or morechemical compounds from a material. The device 100 may include acollector 102, a vacuum pump 104 and a sorbent material (not shown)within a chamber 108. The vacuum pump 104 may be coupled with an end ofthe chamber 108 opposite an end coupled with the collector 102. Tubing110 or other similar apparatus may be used to connect the vacuum pump104 to the chamber 108. The collector 102 may be pressed onto a surfaceand the vacuum pump 104 may be initiated to reduce a pressure over thesurface and volatilize the chemical compounds, such as CWA compounds andchemical attribution signature compounds. The collector 102 may have aseal on an end that contacts the surface. The seal may be a peripheralend of the chamber and may be configured to seal against the surface toprevent fluid from entering the chamber 108 generation of a vacuumwithin the chamber 108, as will be described. Surfaces may include, forexample, glass, plastic, polymeric materials, painted wallboard, paper,and the like. Internal parts of a toy car designed to use vacuum suctioncreated by a fan to crawl on walls, such as an AIR HOGS® toy car, whichis available commercially from Spin Master, Ltd. (Toronto, Canada), maybe used as the vacuum pump 104 in the device 100. For example, thecollector 102 may include a funnel that may be placed over the surfacewhile the vacuum pump 104 is initiated such that volatilized chemicalsmay pass over the sorbent material and may be captured thereon. Thesorbent material may include one or more materials having the capacityto absorb or adsorb chemical compounds of interest. As a non-limitingexample, the sorbent material may include an SPME fiber or othersuitable sorbent, such as activated carbon, synthetic zeolite, orTENAX™.

Referring to FIG. 2, another embodiment of a portable extraction device200 is shown. The device 200 includes a collector 202, a vacuum pump(not shown), a sorbent material (not shown) within a chamber 208, a seal210, a valve 212, a sorbent material injector 214 and, optionally, aconventional pressure transducer 216. The seal 210 may be formed from apolymer material, such as polyvinyl ether or SORBOTHANE®, which iscommercially available from Sorbothane, Inc. (Kent, Ohio). In someembodiments, the vacuum pump may be initiated to reduce a pressure overa surface (not shown) of a material and volatilize the chemicalcompounds such that the device 200 functions as a d-PVE. The chamber 208may be seated over the surface to be sampled, forming a seal over thesurface. Pressure within the chamber 208 volume may be reduced using,for example, the vacuum pump, to increase rates of volatilization of thechemical compounds within the chamber 208.

In other embodiments, the chamber 208 may be evacuated before collectionrather than being continuously connected to the vacuum pump such thatthe device 200 functions as a s-PVE. The valve 212 enables the vacuumwithin the chamber 208 housing the sorbent material to be maintainedprior to use of the device 200 to sample the surface. Once the device200 is placed on the surface, the valve 212 may be opened to expose thesurface to the reduced (i.e., vacuum) pressure within the chamber 208.Exposure of the surface to the reduced pressure within the chamber 208may result in volatilization of chemical compounds on the surface. Thes-PVE may be allowed time to equilibrate, enabling partitioning of asignificant fraction of the chemical compound into the sorbent material.The sorbent material may be fitted within the chamber 208 and mayinclude, for example, a high capacity, fast absorbing SPME fiber. Afraction of the volatilized chemical compounds may partition into thesorbent material, which may then be analyzed at a forensic laboratory byinserting the sorbent material into a heated injector of a TD/GC/MS.

The first end of the chamber 208 may be placed over a target materialbefore opening the valve 212 to the chamber 208. Thereafter, the valve212 is opened, which evacuates the atmosphere over the sampled area andcontained within the chamber 208. This creates a pressure drop over thesurface 216. A sorbent material, such as an SPME may be inserted into asecond end of the chamber 208 to absorb volatilized compounds within thechamber.

Referring to FIG. 3, another embodiment of a portable extraction device300 is illustrated. The device 300 includes a first chamber 308A and asecond chamber 308B, each including one or more ports 306A and 306B forintroducing a sorbent material (not shown), a vacuum source 304, and acollector 310. The device 300 may also include one or more valves 312Aand 312B above the vacuum source at the bottom of the diagram, andrespectively between the first chamber 308A and the second chamber 308B.For example, the vacuum source 304 may be any pump or fan device capableof lowering the pressure in the first chamber 308A and second chamber308B. After placing the vacuum source 304 of the device 300 over atarget material, the vacuum source 304 may be used to reduce pressureover the target material and funnel the vapors into the first chamber308A. The device 300 can be integrated with a simple robotic devicecapable of climbing the walls to enable vacuum extraction of chemicalcompounds on remote surfaces. After the pressure over the surfacebeneath the sampling flange of the collector 310 has been reduced, afirst valve 312A may be closed to seal vapors of volatilized chemicalcompounds in the first chamber 308A, which was actually slightly overatmospheric pressure. The sorbent material, such as an SPME, may then beinjected or inserted into the first chamber 308A via a first septum 309Adisposed opposite a first convection gauge 311A to absorb the chemicalcompounds. The second valve 312B may then be opened to expose thecontents in the first chamber 308A to the vacuum that had previouslybeen created in the second chamber 308B. Another SPME may then beinserted into the second chamber 308B via a second septum 309B disposedopposite a second convection gauge 311B. The second SPME exposed to thereduced pressure environment showed a greater collection of targetcompounds than did the first SPME under higher pressure.

FIGS. 4A through 4C show an embodiment of a field vacuum extractiondevice 400 that includes a chamber 408, a plunger 404, a sorbentmaterial 406 and a seal 410. The plunger 404 has a diameter equivalentto the inside diameter of the chamber 408, such that the plunger 404 isslidably insertable into the chamber 408. A cavity is formed through theplunger 404 by, for example, drilling, longitudinally such that theplunger 404 contains an open, cylindrical void or space extending alonga length of the plunger 404, which is thus open on both ends. The end ofthe plunger 404 is fitted with a stopper material (e.g., stopper 412)that is perforable by a sampling fiber or device, such as an SPME pen(Supelco, St. Louis, Mo.) for delivering the sampling fiber. The seal410 may be formed from a polymer material, such as polyvinyl ether (PVE)or SORBOTHANE®. The aforementioned cylindrical space extends through theplunger 404 and may have a diameter sufficient to pass the sorbentmaterial 406 therethough. The seal may be disposed at a peripheral endof the chamber 408 opposite the end in which the plunger 404 is insertedand may be configured to seal against a sample surface 416 forpreventing fluid from entering the chamber 408 upon retraction of theplunger 404. For example, the field vacuum extraction device 400 may beformed from a polymeric (i.e., plastic), metal or glass syringe modifiedby removing a constriction and a needle lock from a barrel thereof(i.e., the chamber 408), adding a sealing gasket (i.e., the seal 410)between the sample surface 416 and the chamber 408, and replacing aconventional plunger with the plunger 404, which is sized and configuredto accommodate a sorbent material 406, such as a conventionalsolid-phase microextraction (SPME) fiber. Use of a plastic syringeprovides a lightweight, inexpensive and rugged field vacuum extractiondevice 400.

The plunger 404 may be formed from a material such as plastic, TEFLON®(i.e., polytetrafluoroethylene) or other material, such as metal. Asshown in FIG. 4A, the field vacuum extraction device 400 may be placedover the surface 416 to be sampled and the plunger 404 may be retractedto create a modest vacuum over the surface 416, which is made possibleby the seal 410. Optionally, the field vacuum extraction device 400 mayinclude an actuation device 425 (shown in broken lines) to facilitateretraction of the plunger 404, as will be described in further detail.Having retracted the plunger 404, the sorbent material 406 (i.e., theSPME fiber) may be inserted through the cylindrical open space withinthe plunger 404, as shown in FIG. 4B. The sorbent material 406 may beextended into the chamber 408 by perforating a stopper 412 on the end ofthe plunger 404, such that a portion of volatilized chemical compoundswithin the chamber 408 may be absorbed by the sorbent material 406, asshown in FIG. 4C. The sorbent material 406 may be retracted and storedfor transport back to a laboratory for analysis using standard gaschromatography (GC) or gas chromatography mass spectrometry (GC/MS)instruments that are common to most laboratories, such as forensic oruniversity facilities.

As a non-limiting example, two or more SPME pens with sorbent materialmay be used with a single field vacuum extraction device 400 withmodifications to the plunger 404. Additional sorbent materials of thesame type may provide duplicate samples for verification or storage forfuture reference, such as for forensic evidence. Additional sorbentmaterials of different types, such as having different chemicalselectivity, may be used to broaden the range of chemical compoundsbeing analyzed.

The field vacuum extraction device 400 may be used to collect or recovera single chemical compound or multiple types of chemical compounds fromthe surface 416 of the sample. For example, the field vacuum extractiondevice 400 may be used to recover samples having vapor pressures atabout 20° C. of between about 0.01 torr and about 1 torr, and moreparticularly, between about 0.1 torr and about 0.8 torr. For example,the field vacuum extraction device 400 may be used to collect alcohols,acids, esters, halogenated compounds, sulfides, phosphoryl derivatives,amines, and phosphates. Examples of compounds that may be collectedusing the field vacuum extraction device 400 includediisopropylaminoethane thiol (DIPAE), 2,3-dimercapto-1-propanol(DM-1-P), 3-mercapto-1,2-propanediol (3M1,2PD), N-ethyl diethanol amine(NEDEA), N-methyl diethanolamine (NMDEA), 1,3-propanedithiol (PDT),dithiolane, 2,2′-thiodiethanol (thiodiglycol or TDG), diethyldithiophosphate (DEDTP), diethyl methylphosphonate (DEMP), diisopropylmethylphosphonate (DIMP), dipinacolyl methylphosphonic acid (DPMP),diethyl ethylphosphonate (DEEP), diethyl phosphite (DEPt), O-ethylmethylphosphonothioate (EMPT), triethyl phosphite (TEPt),2-chloroethylethylsulfide (CEES), ethyl dichlorothiophosphate (EDCTP),esters of ethyl dichlorophosphate (EDCP), 1,3-propanedithiol (1,3-PDT),2,2-tetrachlorodiphenylethane (2,2-TDE), and N-methylethylenediamine(NMEDA). Analysis of recovered samples was performed primarily on aGC/MS, but also on a GC only instrument. There are some differences inthe response of the two analytical instruments, which is due to thedifference in columns each instrument used and not to the PVE deviceitself. The parts exposed to the volatilized chemical compounds aredisposable and inexpensive, so there is no carry over from one sample tothe next. Because the field vacuum extraction device 400 requires onlyoperator power (i.e., no external power source), includes lightweight,inexpensive and disposable parts, and does not required large apparatussuch as valves, pumps or fans, the field vacuum extraction device 400 iswell suited for collection of chemical compounds in the field. Althoughexamples of materials that may be used to form the field vacuumextraction device 400 are provided herein, the present disclosure is notlimited to particular materials.

As shown in FIGS. 4D through 4E2, the field vacuum extraction device 400may additionally include at least one of a pressure transducer and apressure sensor. Since reducing the pressure within the chamber 408 ofthe field vacuum extraction device 400 enables the volatilization andcollection of the target compounds, use of the pressure sensor (e.g., apressure transducer) is useful in determining if a desired reduction inpressure has been achieved, or if the field vacuum extraction device 400has been compromised.

Referring to FIGS. 4D1 and 4D2, the chamber 408 may include a pressuresensor 414. For example, an opening 418 may be formed through a wall 417of the chamber 414 and the pressure transducer 414 may be insertedthrough the opening 418. The pressure sensor 414 may be a pressuretransducer or any other element for sensing pressure. The pressuresensor 414 may be sealed within the opening 418 so that pressure (e.g.,a sub-ambient, vacuum pressure) may be maintained within the chamber408. To create a seal between the pressure sensor 414 and the opening418, and o-ring (not shown) or other suitable seal may be placed betweenthe pressure sensor 414 and surfaces of the opening 18. Duringretraction of the plunger 404, as shown in FIG. 4D2, the pressure sensor414 may be used to detect a reduction in pressure in the chamber 408, orto determine a change in pressure within the chamber 408.

As shown in FIGS. 4E1 and 4E2, a recess, such as indentation 420, may beformed in the wall 417 of the chamber 408. For example, the indentation420 may include a section of a flexible or semi-flexible material 420 athat functions as a diaphragm during use of the field vacuum extractiondevice 400 by moving into the chamber 408 as the pressure within thechamber 408 is reduced in comparison to pressure outside the chamber408. The indentation 420 may be formed during molding of the chamber 408or by, for example, thinning a portion of the wall 417 of the chamber408. As another non-limiting example, the indentation 420 may be formedby attaching a flexible or semi-flexible material to an aperture in thewall 417 of the chamber 408 (such as the opening 418 shown in FIGS. 4D1and 4D2). The flexible or semi-flexible material may be attached to thewall 417 of the chamber 408 using a conventional adhesive or aconventional welding process, for example.

The pressure within the chamber 408 may be monitored colorimetricallyusing a pressure sensitive agent (e.g., a pressure sensitive paint or apressure sensitive pigment). Referring to FIG. 4E1, the pressuresensitive agent (not shown) may be disposed in a void 422 formed byindentation 420 in the wall 417 of the chamber 408 such that thepressure sensitive agent is exposed to pressures within the chamber 408during retraction of the plunger 404. As another example, the pressuresensitive agent may be disposed within a container (not shown) attachedto an aperture in the wall 417 of the chamber 408 (such as the opening418 shown in FIGS. 4D1 and 4D2). The container may be formed from atransparent or semi-transparent material (e.g., plastic or glass),enabling observation of the pressure sensitive agent through thecontainer during collection. Disposing the pressure sensitive agentwithin the void 422 or within the container prevents disruption ordisplacement of the pressure sensitive agent 420 by the plunger 404during retraction of the plunger 404.

For example, the pressure sensitive agent may be a pressure sensitivepaint that includes oxygen sensitive luminescent (e.g., fluorescent orphosphorescent) molecules and a binder. As a partial pressure of oxygenwithin the chamber 408 changes as the plunger 404 is retracted, avisible change in the color and/or intensity of the pressure sensitiveagent occurs, enabling detection of a pressure change. Depending on thetype of pressure sensitive agent, an ultraviolet light source or anoptical spectrometer may be used to illuminate the pressure sensitiveagent to determine the color and/or intensity change. Since the pressuresensitive agent may be adversely affected by temperature changes, atemperature sensitive agent (e.g., a temperature sensitive paint or atemperature sensitive pigment) may be combined with or used inconnection with the pressure sensitive agent to monitor such temperaturechanges. The pressure sensitive agents and temperature sensitive agentsmay be tested with the potential target compounds to determine chemicalcompatibility prior to collection. For example, particular targetcompounds may quench luminescence of a particular pressure sensitiveagent rendering such a pressure sensitive agent unsuitable for use incollection of such target compounds. The pressure sensitive agentprovides a light weight and cost effective means of determine pressurechanges during extraction.

After determining that that the vacuum has been formed within thechamber 408 using the methods described with respect to FIGS. 4D1through 4E2, the sorbent material (not shown) may be extended into thechamber 408, retracted and stored as described with respect to FIG. 4C.

Heat may also be utilized to improve volatilization of the targetcompounds from a surface, thus improving collection of the targetcompounds. Referring to FIG. 4F, a heat source 424 may be associatedwith the field vacuum extraction device 400 to improve collection of thetarget compounds. For example, as shown in to FIG. 4F, the heat source424 may be disposed around at least a portion of the chamber 408.Increasing the temperature of the walls 417 of the chamber 408 or withinthe chamber 408 by about 10° C. may significantly improve volatilizationand collection of the target compounds. By way of example and notlimitation, the heat source 424 may be heated to a temperature of lessthan or equal to 200° C., such as, between about 35° C. and about 113°C. For example, the heat source 424 may include a thermite material(i.e., a composition of a metal powder and a metal oxide) within anenvelope that may oxidize to generate heat upon exposure to oxygen. Byway of example and not limitation, the heat source 424 may be formed byreshaping conventional hand warmers into a donut-shape or arectangular-shape. The heat source 424 may be secured around the chamber408 using an adhesive (e.g., tape) or a VELCRO® closure. As otherexamples, the heat source 424 may include an infrared or UV lightsource. Utilizing the heat source 424 to heat the chamber 408 improvescollection of the target compounds by volatilizing target compounds onthe surface 416 of the sample as well as target compounds that maycondense on surfaces (e.g., inner surfaces of walls 417) with in thechamber 408. In the presence of the heat source, the sorbent material406 may be extended into the chamber 408, retracted and stored asdescribed with respect to FIG. 4C.

Referring back to FIG. 4A, the field vacuum extraction device 400 mayoptionally include the actuation device 425 to facilitate retraction ofthe plunger 404 and improve collection of the target compounds. Forexample, the actuation device 425 may include a drill device with aswivel joint, a linear actuator (e.g., a rack and pinion arrangement) ora worm gear. Such actuation devices 425 are known in the art and are notdescribed in detail herein. In embodiments in which the actuation device425 includes the rack and pinion arrangement, the rack may be attachedto the plunger 404 and the pinion may be driven manually or with a motorto remove the plunger 404 from the chamber 408. In embodiments in whichthe actuation device 425 includes a drill device with a swivel joint,the swivel joint may be attached to the plunger 404 and the drill may beactuated to remove the plunger 404 from the chamber 408.

As shown in FIGS. 4G1 and 4G2, the actuation device 425 may be anextraction system that mechanically assists in extraction of the plunger404. As shown in FIG. 4G1, the extraction system may be integrated withthe chamber 408 and may include a spring 426, an assist barrel 428, amating disc 430, a latch 432 and a spring holder 434. The mating disc430 of the extraction system 425 may be engaged with the plunger 404 andthe spring 426 may be disposed between a base of the chamber 408 and thespring holder 434. Prior to retracting the plunger 404, the latch 432may be engaged with a stop 436 on the chamber 408 such that the spring426 is compressed. The stop 436 may be positioned to enable the plunger404 to be retracted to a predetermined height, as will be described.

Referring to FIG. 4G2, the latch 432 may be released, such as by turningthe latch 432 to align the latch 432 with a groove in the stop 436through which the latch 432 may pass, such that the spring 426decompresses and exerts a force on the plunger 404 via the mating disc430. The force exerted on the plunger 404 moves the plunger 404 upwardout of the chamber 408 (i.e., in a direction opposite the surface 416 ofthe sample). As the spring holder 434 comes into contact with the stop436 on the chamber 408, the upward motion of the plunger 404 ceases.After the plunger 404 stops moving, the sorbent material 406 (e.g., theSPME pen) may be inserted into the chamber 408 as described with respectto FIG. 4C.

The field vacuum extraction device 400 may also include features thatenables collection of target compounds from samples having non-planar oruneven (i.e., rough) surfaces, such as rocks, soil, fabric, etc.Referring to FIGS. 4H1 and 4H2, the field vacuum extraction device 400may include a sample cup 440 including a lip 442 that aligns with theseal 410. As shown in FIG. 4H1, the sample 415 may be placed in thesample cup 440 and the sample cup 440 may be sealed to the chamber 408.As shown in FIG. 4H2, the plunger 404 may be retracted such thatcompounds are volatilized from the sample 415. After the plunger 404 hasbeen retracted from the chamber 408 to form a vacuum within the chamber408, the sorbent material (not shown) may be extended into the chamber408, retracted and stored as described with respect to FIG. 4C.

EXAMPLES Example 1

To standardize comparison, test samples were prepared including 400 μgof tributyl phosphate (TBP) on filter paper (WHATMAN® Grade 41quantitative filter paper, which is commercially available from WhatmanInc., Piscataway, N.J.) and/or glass.

FIGS. 5A and 5B show a schematic comparison of design and function ofextraction of compounds of interest 501 using an SPME fiber 506overlying test samples 516 at atmospheric pressure and in the presenceof a vacuum pressure. There are multiple interactions that havedifferent equilibrium and kinetic rates. There is the rate ofvolatilization of the target compounds from the surface material, therate that the target compounds sorb onto the parts of the device (i.e.,the wall of the chamber), and the rate that the target compounds sorb tothe SPME fiber. FIG. 5A illustrates that the amount of target compoundthat could be sorbed onto the SPME fiber in the headspace at atmospherewould be rather low, if seen at all. However, a small vacuum placed overthe sample as illustrated in FIG. 5B increases the volatilization of theanalyte or target compounds from the surface of test samples 516. Whilereducing the pressure will increase the volatilization of targetcompound(s), there are other competing processes that affect the designof a vacuum extraction device, such as the equilibrium and kineticsassociated with the sorption of the target compound(s) onto the SPMEfiber 506 as illustrated in the expanded view in FIG. 5B. Theinteraction of the target compound(s) with the wall 508 of the vacuumchamber is not illustrated.

The devices described herein may be optimized to balance theinteractions. As a non-limiting example, the chamber of any of theembodiments of the devices of the present disclosure may be heated tosubstantially reduce or eliminate sorption or adherence of the targetcompound to surfaces of the chamber.

FIGS. 6A through 6C provide a comparison of sample collection from atest sample using an SPME as a sorbent material in the devices describedwith respect to FIGS. 2 and 3 with sample collection at atmosphericpressure. FIG. 6A is a chromatogram of the sample collected with theSPME at atmospheric pressure. FIG. 6B is a chromatogram of the samplecollected using the device similar to that shown in FIG. 1 using avacuum pump (i.e., a d-PVE) to reduce pressure over the sample surfaceand an SPME used as the sorbent material placed within a flow pathbetween a sample surface and the vacuum pump. FIG. 6C is a chromatogramof the sample collected using the device 200 shown in FIG. 2 having apre-evacuated chamber (i.e., a s-PVE) used to reduce pressure of thesample surface. As shown in FIGS. 6B and 6C, an increased amount ofsample is detected using either embodiment (i.e., d-PVE or s-PVE) incomparison to an amount of sample collected at atmospheric pressure(FIG. 6A). While not wishing to be bound by any particular theory, thedevice 200 described with respect to FIG. 2 may have increasedcollection efficiency using a pre-evacuated chamber in comparison tousing a device with a continuous vacuum pump, as described with respectto FIG. 1, because there is more time for the target compounds toequilibrate with the sorbent fiber in the s-PVE design, while the amountof time required to establish equilibrium between the volatilizedchemical compounds and the SPME may exceed the residence time of thetarget compounds in a d-PVE chamber.

In a dynamic portable vacuum extractor (d-PVE) device, the chemicalcompounds may stream past the SPME and ultimately into and out of thevacuum pump resulting in a decrease in collection by the sorbent fiber.Thus, even though the pressure readings for both experiments were thesame above the sample, the s-PVE device 200 having the pre-evacuatedchamber, may have increased effectiveness due to the increase ofresidence time of the vapors with the SPME. The effect is shown indramatic fashion by the experiment represented by FIG. 6D, in which atributyl phosphate (TBP) response increases steadily over a thirty (30)minute timeframe when sampled using the portable extraction device 200shown in FIG. 2 as a s-PVE. These experiments suggest that a minimumpressure that the pre-evacuated chamber of the static device should beat about 50 torr when exposed to the SPME.

Example 2

Tests were conducted to determine which type of SPME fiber works bestfor detecting the CAS of interest. Some of the SPME fiber types testedinclude 100 μm polydimethylsiloxane, 85 μm polyacrylate, 75 μmcarboxen-polydimethylsiloxane, 85 μm carboxen-polydimethylsiloxane, 65μm polydimethylsiloxane-divinylbenzene, and 7 μm polydimethylsiloxane.Even for a given fiber material (e.g., polydimethylsiloxane), thephysical characteristics also play a role in how well the SPME absorbsan analyte. As illustrated in FIGS. 7A through 7C, there may be asubstantially significant difference in response for the same CASanalyte for different fiber types. FIG. 7A is a gas chromatogramobtained for DIMP using the 7 μm polydimethylsiloxane. FIG. 7B is a gaschromatogram obtained for DIMP using the 65 μmpolydimethylsiloxane-divinylbenzene. FIG. 7C is a gas chromatogramobtained for DIMP using the 85 μm carboxen-polydimethylsiloxane. The 85μm carboxen-polydimethylsiloxane demonstrated improved performance overthe other SPMEs tested, which may be generally applied to absorption oforganic analytes.

Example 3

Trace quantities of CAS compounds were applied to surfaces and weresampled using the portable extraction device 200 described with respectto FIG. 2, which produced exposed SPME fibers that were analyzed usingTD/GC/MS. Glass was chosen for a non-absorptive surface because it is amatrix that is of significant forensic value, and because its surfacecould be effectively cleaned, removing background from the subsequentGC/MS analyses that were performed. This latter consideration isimportant because it simplified the analyses and subsequentinterpretations, easing identification of signature compounds,impurities and degradation products.

Diethylphosphite (DEPt) is a relatively small molecule, which may leadto the expectation that it may readily partition into the gas phase, andperhaps volatilize before it could be effectively sampled. However, DEPtalso has a significant P—O (phosphorous-oxygen) dipole that may producevery strong bonding with both Lewis and Bronsted acid/base sites foundon matrix surfaces. This factor may result in longer persistence onsurfaces.

The portable extraction device 200 was placed over a glass surface towhich DEPt had been applied. The valve of the portable extraction device200 was opened, and the SPME fiber was exposed to a vacuum environmentfor five (5) minutes, after which time the valve was closed. As shown inFIGS. 8A through 8C, analysis of the SPME fiber principally showed airdetected at retention times (RT) of less than about two (2) minutes, andcolumn bleed at a RT of about 25 minutes. Referring to FIG. 9, a smallpeak at a RT of about 13.4 min was ascribed to DEPt on the basis of itsmass spectrum. FIGS. 9 and 10 illustrate a low abundance ion as m/z 138corresponds to the DEPt molecular ion, which undergoes facileelimination of a C₂H₃ radical to furnish m/z 111, and a serialelimination of C₂H₄ and or C₂H₅OH to make m/z 83 and m/z 65,respectively. The overall response of the GC/MS is modest, however,examinations of the single ion chromatograms shown in FIGS. 8B and 8Cshow that the traces for both m/z 111 and m/z 83, respectively, are wellabove background, indicating that lower quantities may be well abovedetection limits. Other small peaks observed in the chromatogram hadmass spectra that corresponded to PDMS that likely originated eitherfrom the SPME or from the column.

Referring to FIGS. 11A through 11C, analysis of triethyl phosphate (TEP)applied to glass surfaces resulted in a GC/MS chromatogram thatcontained four peaks, all of which were likely derived from TEP or are acarryover from prior experiments. FIG. 12, which is a mass spectrum ofcompounds eluting at a RT of about 10.9 minutes, displayed a massspectrum that corresponds to intact TEP, as indicated by a low-abundancepeak at m/z 182 that is consistent with the ionized molecule. Severalabundant fragment ions that arise from losses of C₂H₃ radical (formingm/z 155) and subsequent losses of C₂H₄ and or H₂O. Serial losses of twoC₂H₄ molecules from m/z 155 produce [H₄PO₄]⁺at m/z 99, which is typicalof fragmentation seen in the mass spectra of the trialkylphosphatederivatives. FIG. 13 is a mass spectrometric fragmentation of TEP.

As shown in FIG. 11C, m/z 99 is a strong indicator for the presence ofthe trialkylphosphates. In several analyses, other peaks were observedat a RT of about 5.3 minutes, about 6.6 minutes and about 8.1 minutes.The mass spectra of these compounds clearly indicated that they wereorganophosphorus compounds. The abundant ion at m/z 79 is suggestive ofmethyl phosphonate derivatives, as previously discussed, and it isprominent in the spectra of compounds eluting at about 5.3 minutes andabout 6.6 minutes, which are shown in FIG. 11B.

FIG. 14 is a mass spectrum for the peak at a RT of about 5.3 minutes andcontains abundant peaks at m/z 80 and m/z 79 that indicatedimethylphosphite (DMPt). DMPt did not likely originate from degradationof TEP and, thus, may an impurity in the TEP standard, or an impurityderived from carryover of the DEPt. DMPt was not seen in the DEPtanalysis, however, it may be formed by alkoxy exchange with the methanolsolvent. FIG. 15 is schematic diagram of mass spectrometricfragmentation for DMPt.

FIG. 16, which shows the mass spectrum of a compound eluting at a RT ofabout 6.65 minutes, is consistent with ethyl methyl phosphite (EMPt), inwhich case the abundant ion at m/z 97 arises from elimination of theC₂H₃ radical, a process that is followed by dehydration to form the ionat m/z 79. FIG. 17 is a proposed mass spectrometric fragmentation forEMPt.

Referring to FIG. 18, a mass spectrum of compound eluting at a RT ofabout 8.05 minutes that is indicative of DEPt is depicted (see also FIG.9).

As shown in FIG. 19, ethyl methylphosphonic acid (EMPA) is both asynthon for, and a degradation product of 2-S(diisopropylaminoethyl)O-ethyl methylphosphonothiolate (VX). Diisopropylaminoethanethiol (DESH)is also a hydrolysis product of VX. The methylphosphonic acids aremoderately strong acids, having pK_(a) values of between about 2.3 andabout 2.5, and hence may be present in the conjugate base form in manyenvironments. This phenomenon serves to make volatilization difficult,and in fact, the EMPA conjugate base will strongly bind to manysurfaces. Nevertheless, the PVE was able to volatilize and absorb asignificant amount of DEMP, which is the esterified acid EMPA, asindicated by a strong signal at a RT of about 17 minutes in the totalion chromatogram, as shown in FIG. 20A.

The gas chromatograms shown in FIGS. 20A through 20C and the massspectrum shown in FIG. 21 establishes the identity of DEMP, with a lowabundance ion at m/z 152 corresponding to the protonated molecule. Theintense ion at m/z 125 arises by elimination of the C₂H₃ radical, andundergoes a further fragmentation by loss of C₂H₄ to form m/z 97,followed by loss of H₂O to form m/z 79 as shown in FIG. 22.

TBP is the least volatile of the compounds in this example. It has amolecular weight of 266 g/mol, nearly equivalent to VX, is highlylipophilic, and strongly adsorbs to surfaces through Lewis base/acidinteractions of the phosphoryl group. For these reasons it is used as astimulant for VX, however TBP is also of interest because it is used asan extractant in nuclear fuel reprocessing. As shown in FIGS. 23Athrough 23C, a gas chromatogram measured from a PVE sample of glassexposed to TBP showed a poorly resolved peak at about 18 minutes.Another peak at 18.7 min is likely hexyl, dibutyl-phosphate that ispresent as an impurity in the TBP. The profile of the chromatographicpeak, no doubt, is due to adsorption occurring at the injector or in theMS interface, indicating that chromatographic optimization is needed formore condensable, less volatile compounds. Despite the chromatographicproblems, the mass spectrum correlated with that of TBP (FIGS. 24 and25).

As shown in FIG. 26, mass spectra of other compounds observed in theGC/MS analysis appeared to be TBP-related. A spectrum of compound at aRT of about 18.7 minutes, which is shown in FIGS. 23A through 23C,contains the same ensemble of peaks, as does TBP, but with severaladditional peaks. For example, the ion at m/z 183 is 28μ higher than m/z155, suggesting the presence of a hexyl substituting for one of thebutyl groups, in which case the identity of the compound may be hexyl,dibutylphosphate. This assignment is supported by the abundant ion atm/z 85 that may be derived from the hexyl cation C₆H₁₃ ⁺ but does notaccount for the low abundance ion at m/z 255, and so this compound hasnot yet been identified.

In addition to the peak at retention time 18.7, there were several lowerabundance compounds eluting between about 20 and about 20.5 minutes thatwere unquestionably butyl organophosphoryl in nature, as indicated bythe single ion chromatograms for m/z 99 and m/z 155 (FIGS. 23A through23C). These compounds either could be derived from reactions occurringon the glass surface, or are present as impurities in the TBP spikesolutions. Their appearance shows that the PVE sampling is picking upsynthetic impurities in the synthetic mixtures.

Example 4

A matrix of high priority is painted wallboard (PWB), because it is avery common fixed surface in many indoor environments. Compared withglass, it may be expected that the PWB may present different challengesfor sampling CAS compounds, in part because the organic, painted coatingwill be absorptive, and in part, because a high chemical backgroundmight obscure the GC/MS signature of the CAS compounds. In this example,a portable vacuum extraction according to an embodiment of the presentdisclosure was used to sample chemical compounds from a surface ofpainted wallboard.

FIGS. 27A through 27C are TD/GC/MS profiles of DMMP collected frompainted wallboard. Initial GC/MS chromatograms showed a backgroundderived from the painted wallboard was significantly higher incomparison to a background derived from the glass surfaces, particularlyat RT values of about 20 minutes. However, the DMMP that was added tothe painted wallboard was detected at about 7.8 minutes. Referring toFIG. 28, a mass spectrum showed a low abundance molecular ion at m/z124, with all other significant fragment ions interpreted in terms oflosses of formaldehyde, a methoxy radical, and or a methyl radical. Theindividual ion chromatograms did not reveal any further DMMP-derivedions. FIG. 29 is the schematic for the mass spectrometric fragmentationfor DMMP.

FIGS. 30A through 30B are a collection of TD/GC/MS profiles of DESHhydrochloride applied to glass. N,N-diisopropylaminoethane thiol (DESH)is both a synthon for, and a degradation product of VX (FIG. 19). Thechromatographic profile showed a broadened two-topped peak at RT ofabout 17 minutes, with a four-minute leading edge. Referring to FIGS.30B and 31, the mass spectra demonstrate that the compound eluting atabout 27.1 minutes may be either DESH, or a closely related compound. Asshown in FIG. 32, elimination of the HSCH₂ radical from the DESH radicalcation produces m/z 114, which then eliminates C₃H₆ to furnish m/z 72.Loss of the HS radical accounts for formation of m/z 128, whichsurprisingly is not detected; instead, an abundant ion at m/z 86 isformed, which may ordinarily be rationalized as loss of C₃H₆ from m/z128; m/z 86 eliminates C₃H₆ to form m/z 44.

Referring back to FIG. 30C, the m/z 86 ion profile shows that it is notassociated with m/z 114, and instead arises from a compound elutingabout 0.4 minute later and at about 27.5 minutes. FIG. 33 is a massspectrum of compound eluting at a RT of about 27.5 minutes. While notwishing to be bound by any particular theory, it is believed that them/z 86 ion structure is that of the protonated isopropylaziridiniumcation, that may be formed from further reaction of the amine moiety ofthe DESH precursor. For example, in solution the ethyl diisopropylaminemoiety is known to dimerize forming the N,N,N′,N′-tetraisopropylpiperazine dication, and decomposition of this compound may well produceN,N′-diisopropyl piperazine that may be expected to fragment by formingthe isopropylaziridinium cation. FIG. 34 provides a scheme for theformation of ions at m/z 86 and m/z 44 from slow-eluting compoundsrelated to DESH, which, while not wishing to be bound by any particulartheory, are believed to be piperazine derivatives that are collected bythe vacuum extractor device.

The devices and methods of the present disclosure enable efficientsampling of fixed surfaces contaminated with chemical compounds, such asCAS compounds. Fast and efficient sampling coupled with TD/GC/MSanalysis is expected to provide the forensics community with a tool thatmay provide chemical evidence from an exposed environment, whether ornot actual samples may be easily collected for transport back to thelaboratory.

Example 5

In the following examples, mixtures of chemical compounds in microgramquantities were applied to painted wallboard, and sampled using thefield vacuum extraction device 400 described with respect to FIGS. 4Athrough 4C (i.e., f-PVE) using a polydimethyl-siloxane-based SPME as thesorbent material 408. Subsequent TD/GC/MS analysis of the exposed SPMEshowed recovery of alkyl phosphites, alkyl phosphates, and even theacidic methyl phosphonic acid, which was surprising because acidicmethyl phosphonic acid is well known as a problematic analyte because ofits high surface reactivity. Further experiments were successfullyconducted on samples that had been exposed to acidic phosphonates andphosphoryl halides.

FIGS. 35A through 35C and 36 demonstrate that sulfides and theirhydrolysates are recoverable from a surface using the field vacuumextraction device 400 described with respect to FIGS. 4A through 4C.2-Chloroethyl ethyl sulfide (CEES, which is a surrogate compound for thechemical warfare agent mustard), and a hydrolysate of CEES (i.e.,methoxyethylethyl sulfide (MeOEES)) were applied to a surface of a glasssample. The surface of the glass sample was sampled using the fieldvacuum extraction device 400 and the SPME was analyzed using TD/GC/MSanalysis. The results of the TD/GC/MS analysis obtained from thepolydimethyl-siloxane-based SPME are shown in FIGS. 35A through 35C. Asshown in FIG. 36, CEES and MeOEES and were recovered from the glassusing the field vacuum extraction device 400.

FIGS. 37 and 38 demonstrate that phosphoryl derivatives are recoverablefrom a surface using the field vacuum extraction device 400 describedwith respect to FIGS. 4A through 4C. A mixture of alkyl phosphites wasapplied to a surface of a glass sample. The surface of the glass samplewas sampled using the field vacuum extraction device 400 and the SPMEwas analyzed using TD/GC/MS analysis. The results of the TD/GC/MSanalysis obtained from the polydimethyl-siloxane-based SPME are shown inFIGS. 37 and 38. Dimethyl phosphite (DMPt or DMPite) and diethylphosphite (DEPt or DEPite) were recovered from the glass using the fieldvacuum extraction device 400 as were chemical compounds believed to bederived from the surface and possibly from polymer materials of thefield vacuum extraction device 400, such as those forming the chamber406 or the seal 410. The high number of counts shown in FIG. 37demonstrates that even small quantities of phosphoryl derivatives, suchas phosphites, are recoverable using the field vacuum extraction device400.

FIGS. 39 and 40 demonstrate that amines are recoverable from a surfaceusing the field vacuum extraction device 400 described with respect toFIGS. 4A through 4C. Diisopropylaminoethanol (DIPAE) derived from VXdegradation and synthesis was applied to a surface of a glass sample.The surface of the glass sample was sampled using the field vacuumextraction device 400 and the SPME was analyzed using GC analysis. Theresults of the TD/GC/MS analysis obtained from thepolydimethyl-siloxane-based SPME are shown in FIGS. 39 and 40 and showthat DIPAE was efficiently recovered from the glass using the fieldvacuum extraction device 400. These results were surprising since DIPAEstrongly adsorbs to surfaces and, thus, impedes recovery from thesurfaces using conventional methods.

FIGS. 41 and 42 demonstrate that derivatives of ethyldichlorothiophosphate that are formed in situ are recoverable from asurface using the field vacuum extraction device 400 described withrespect to FIGS. 4A through 4C. Ethyl dichlorothiophosphate (EDCTP) maybe hydrolyzed in the presence of a solvent to form esters. The surfaceof the glass sample was sampled using the field vacuum extraction device400 and the SPME was analyzed using TD/GC/MS analysis. The results ofthe TD/GC/MS analysis obtained from the polydimethyl-siloxane-based SPMEdemonstrate that a di-ester of EDCTP was efficiently recovered from theglass using the field vacuum extraction device 400. A variety ofthiophosphoryl derivatives was also recovered.

A mixture of CAS compounds in microgram quantities were applied topainted wallboard, and sampled using the FVE with apolydimethyl-siloxane-based SPME. The results of the TD/GC/MS analysisof the exposed SPME are shown in FIG. 43 and show recovery of alkylphosphites and alkyl phosphates. The CAS compounds sampled are (fromleft to right) dimethyl phosphite, ethyl methyl phosphite, diethylphosphite, and triethyl phosphate.

FIG. 44 demonstrates that the field vacuum extraction device 400described with respect to FIGS. 4A through 4C will collect a wide arrayof organic compounds from the chemical environment. A sample wascollected from glass exposed to a standard solution of diethyl phosphiteapplied in a solution with methanol. In addition to recovering thiscompound (eluting compounds from the chromatograph at a RT of about 7.8minutes), a second derivative, ethyl methylphosphite was also recovered(eluting compounds from the chromatograph at a RT of about 5.4 minutes).A number of other compounds were also collected and then measured.Although each of these compounds has not been unequivocally identified,FIG. 44 demonstrates that the organic compounds collected are fromseveral chemical families: paraffins (straight and branched), olefins(straight and branched), fluorocarbons, ethers, terpenes, butylatedhydroxytoluene (BHT), and siloxanes.

FIG. 45 demonstrates that the field vacuum extraction device 400described with respect to FIGS. 4A through 4C may be used tocharacterize surfaces that have been exposed to compounds that arereactive or strongly surface adsorptive. FIG. 45 shows a chromatogramgenerated from a sample collected from glass exposed toO-ethyldichlorothiophosphate using the field vacuum extraction device400 described with respect to FIGS. 4A through 4C, and displays a strongpeak corresponding to the methylated ester, which was formed from areaction of the dichloride with solvent on the surface. In addition,distinctive peaks corresponding to diethyl disulfide and diethyltrisulfide are measured. These compounds enable identification of theoriginal exposure mixture.

Example 6

This example involved application of small amounts of CAS compounds tosurfaces that were then sampled using the field vacuum extraction device400 described with respect to FIGS. 4A through 4C, which included SPMEfibers as the sorbent material. The SPME fibers were analyzed usingTD/GC/MS. Compounds were selected in order to mimic as closely aspossible those having forensic value, either because they are used insynthesis, typical synthetic byproducts, or degradation products.Standard solutions were generated for the test compounds by mixing themwith methanol to a concentration of about 10 μg/μl. Dissolution usingmethanol resulted in partial hydrolysis of several of the compounds,which complicated the quantitative interpretation of the experiments,but enriched the compound diversity and provided a better mimic of whatoccurs when an impure CWA is released. Compounds that were formed byhydrolysis reactions are described herein.

Glass was used as a fixed surface as this material is of significantforensic value and because its surface could be effectively cleaned,thereby removing background from the subsequent GC/MS analyses that wereperformed. This latter consideration is important because it simplifiedthe analyses and subsequent interpretations, easing identification ofsignature compounds, impurities, and degradation products. Additionalexperiments used painted wallboard or paper as the fixed surface.

FIG. 46 is a TD/GC/MS obtained from sampling glass exposed to1,3-propanedithiol (PDT) using the field vacuum extraction device 400.PDT was used as a surrogate for mercaptan degradation products, and thestandard contained both PDT and dithiolane. The sulfhydryl functionalgroups of PDT have the potential for strong binding to surfaces, andthus the compound poses a sampling challenge. Dithiolane may result fromintramolecular oxidative coupling and is also of interest because itprovides a simple disulfide compound for evaluation. PDT was applied asa methanolic solution to a glass surface and then sampled using thefield vacuum extraction device 400. Efficient collection of PDT anddithiolane from glass was demonstrated by the chromatogram resultingfrom the analysis of the SPME fiber. The mass spectrum of the compoundeluting at about 5.6 minutes corresponded to PDT, while the compoundeluting at about 6.2 minutes was dithiolane. The intensity of thechromatographic signal for the PDT molecular ion was about 3.2×10⁶counts, and when compared to the background (about 10³ counts), suggeststhat the minimum detectable quantity and, hence, recovery may be on theorder of 40 nanograms (ng) for this compound. The results demonstratethat smaller quantities could be recovered by optimizing collection andanalysis methods.

The molecular ion for dithiolane (m/z 106) was present at an abundanceof 5×10⁶ counts, a value greater than that for the molecular ion forPDT, which did not reflect the relative concentrations in the standardsolution: in the analysis of the standard, the ratio was 3.6×10⁶ countsfor 1,3-propanedithiol (m/z 108) to 1.6×10⁶ for dithiolane (m/z 106).This indicates that the less adsorptive dithiolane may be collected, aresult consistent with the likelihood that PDT is more stronglysurface-bound compared to the dithiolane.

FIG. 47 is a TD/GC/MS of a sample obtained from glass exposed to2,2′-thiodiethanol (thiodiglycol or TDG) using the field vacuumextraction device 400. The trace in the finer line is the total ionchromatogram and the trace in the thicker line is the m/z 61 single ionchromatogram. Sampling of glass exposed to the TDG solution produced asample chromatogram with a tailing peak at about 8.6 minutes. Single ionchromatograms for the diagnostic mass spectrometric peaks at m/z 104 andm/z 61 were well above background, again suggesting that recovery ofnanogram quantities is possible. Overall signal-to-noise was excellent,however, the results may indicate more aggressive surface binding by thehydroxyl groups of TDG compared to the sulfhydryl groups of PDT (FIG.46). Other peaks in the chromatogram were derived from a variety ofesters, terpenes and the plasticizer butylated hydroxytoluene (BHT).

FIG. 48 provides results of sampling glass exposed to2,3-dimercapto-1-propanol (DM-1-P) using the field vacuum extractiondevice 400. Analysis of the sample generated a complex samplechromatogram consisting of major peaks derived from terpenes, a fewfluorocarbons, diphenyl ether, butylated hydroxytoluene and otherindigenous “background” compounds. DM-1-P did not appear as an intensepeak compared to the rest of the chemical background, but was readilyidentified on the basis of salient ions at m/z 106 and m/z 90 (losses ofH₂O and H₂S from the molecular ion at m/z 124, respectively). Theseappear as tailing peaks at around 8 minutes. Trimercapto propane, animpurity originally observed in the analyses of the solution standard,was not observed.

FIG. 49 provides results of sampling glass exposed to diethyldithiophosphate (DEDTP) that presented multiple sampling challengesbecause the compound used for the standards contained significantimpurities, and as a result the exposure resulted in delivery ofmultiple compounds. Hence, the chromatogram from the TD/GC/MS analysisof the sample obtained using the field vacuum extraction device 400 wascomplex. Seven different DEDTP-derived compounds were recovered by thePVE and identified on the basis of their mass spectra. The compounds areindicated in FIG. 49 as follows: (a) O,O′-diethyl-S-methylthiophosphate, (b) O,O′,O″-trimethyl thiophosphate, (c) O,O′,S-trimethyldithiophosphate, (d) DEDTP, (e) triethyl dithiophosphate isomer, (f)O,O′-diethyl-S-methyl dithiophosphate, and (g) O,O′,S-triethyldithiophosphate. The impurities arise from hydrolysis occurring eitheron in the standard compound, in the sample solution where methanol wasused as a solvent, or on the surface. These reactions result information of higher ethyl and methyl derivatives, which are present inthe standard solution along with DEDTP. Many of these compounds may alsoform in a CWA release environment, particularly if decontaminationtechniques were applied before sampling occurred since decontaminationgenerally results in at least one of hydrolysis and oxidation.

FIG. 50 is a TD/GC/MS analysis of sample obtained from glass exposed toa 2-chloroethyl ethyl sulfide (CEES) standard solution using the fieldvacuum extraction device 400. CEES was included in the array of testcompounds because it is a surrogate for mustard gas (H), which is intactbis(2-chloroethyl)sulfide. The standard contained not only CEES, butalso methoxyethyl ethyl sulfide, which was formed as a result ofmethanolysis occurring in the standard solution, and both compounds wereidentified in abundance in the chromatogram generated from the analysisof the PVE sample. The signature mass spectrometric ion upon whichminimum detection would be made is m/z 75 for both compounds(corresponding to [C₂H₅S═CH₂]⁺), and was about 10⁴ times greater thanbackground. Given that the exposure quantity here was about 20 mg ofeach compound, the signal-to-noise ratio demonstrates that collectionand detection of about 2 nanograms (ng) may be achieved using the fieldvacuum extraction device 400.

FIG. 51 is a TD/GC/MS analysis of sample obtained from glass exposed toa diethyl methylphosphonate (DEMP) solution using the field vacuumextraction device 400. Like DEEP, Diethyl methylphosphonate (DEMP) isboth a synthetic byproduct and hydrolysis product of VX manufacture andrelease. It does not undergo appreciable hydrolysis, and is not asstrongly surface active as hydroxyl or sulfhydryl compounds, and henceit is efficiently recovered from surfaces using the PVE. The TD/GC/MSchromatogram of the PVE SPME sample is fairly simple, with a dominantcompound eluting at about 8.8 minutes having a mass spectrumcorresponding to DEMP.

The quantitation ion at m/z 125 (loss of C₂H₃ from the DEMP molecularion) has a signal-to-noise in excess of 10⁴, suggesting detection ofquantities in the low nanogram range is possible with the PVE-analysisapproach used here. It is worthwhile noting that triethylphosphate wasalso detected eluting at 10.6 min; this compound was a trace impurity inthe DEMP standard solution.

FIG. 52 is the chromatographic output of the TD/GC/MS analysis of sampleobtained from glass exposed to a diethyl phosphite (DEPite) using thefield vacuum extraction device 400. The top chromatogram is a total ionchromatogram and the bottom chromatogram includes a total ionchromatogram and a single ion chromatogram for m/z 155 expanded onehundred times and a single ion chromatogram for m/z 111 expanded onehundred times. The diethyl phosphite (DEPite) standard solutioncontained a significant quantity of ethyl methyl phosphite (EMPite), andtraces of diethyl ethyl phosphonate (DEEP) and triethylphosphate (TEP).Both the DEPite and EMPite were readily recovered using the field vacuumextraction device 400, and detected in the TD/GC/MS chromatogram elutingat about 7.8 minutes and about 6.4 minutes, respectively (FIG. 52, top).Abundances of the quantitation ions suggested recovery/detection limitsin the tens of nanograms range may be readily achievable. Both the TEPand DEEP were also detected well above background (FIG. 52, bottom). Thedetection of DEMP is significant because it was present in the standardat a concentration about 0.005 times the DEPite concentration, whichimplies that the quantity of these compounds deposited on the glass wason the order of 80 ng. The DEMP quantitation ion signal was about twentytimes background. Detection of this quantity was consistent withdetection limit estimates based on a signal-to-noise ration of the majorcompounds, and suggests that the latter estimates are overestimates.

FIG. 53 is a TD/GC/MS analysis of sample obtained from glass exposed toan O-ethyl dichlorothiophosphate (EDCTP) solution using the field vacuumextraction device 400. An abundant peak corresponding to O,O′,O″-ethyldimethylthiophosphate eluted at 9.4 minutes. This ester was produced bymethanolysis of the dichloride in the standard solution. Two other minorpeaks were also observed, diethyl disulfide eluting at about 7.2minutes, and diethyl trisulfide eluting at about 10 minutes. Thesecompounds are the result of oxidative coupling of ethyl mercaptan, adegradation product of ethyl dichlorodithiophosphate. Of interest arecompounds that were present in the standard solution, but were notsampled from the glass. Because the EDCTP is a reactive compound,several additional compounds were present, viz., EDCTP itself,O,O′-ethyl, methyl chlorothiophosphate, and O,O′-diethylchlorothiophosphate. While not wishing to be bound by theory, the chlorocompounds may have reacted with the glass surface, forming anon-extractable adduct, or may have completely hydrolyzed in themethanol solvent, forming acids that may not volatilize, or go throughthe GC column.

FIG. 54 is a TD/GC/MS analysis of sample obtained from glass exposed to40 μg of diisopropyl methylphosphonate (DIMP) using the field vacuumextraction device 400, which eluted at about 7 minutes. In addition, atrace impurity in the DIMP standard solution, triisopropyl phosphate(TIP) was also picked up, and clearly identified at about 8.32 minutes.The fraction of the standard that was TIP was on the order of ×10⁻³,suggesting that about 80 ng was initially present on the glass. Thesignal-to-noise ratio of the salient ions is on the order of 20,indicating that collection and measurement of quantities in the lownanogram range should be possible.

FIG. 55 is a TD/GC/MS analysis of sample obtained from glass exposed todiisopropylaminoethanol (DIPAE) using the field vacuum extraction device400. The DIPAE standard solution produced a TD/GC/MS analysis with thetarget compound eluting at about 9.46 minutes. DIPAE is a hydrolysisproduct of VX, and may also form from VX hydrolysis. Hence, it is animportant CAS compound. The abundance of the peak suggests thatdetection into the low nanogram range should be readily achievable. Inaddition, an earlier eluting peak displayed a mass spectrum consistentwith vinyl diisopropylamine, and while this was barely noticeable in thetotal ion chromatogram, it was readily apparent using the target ion atm/z 86 (corresponding to an ion composition of [(i-Pr)(vinyl)NH₂]⁺].Recovery of a small trace of impurity validates the efficacy of thefield vacuum extraction device 400 for sampling CAS compounds.

FIG. 56 is a TD/GC/MS analysis of sample obtained from glass exposed toethyl methylphosphonic acid (EMPA) using the field vacuum extractiondevice 400. The intact acid is not sampled, however, the ethylderivative diethyl methylphosphonate (DEMP) is formed in situ, and iseffectively sampled using the FVE device. A rich background of organicsis also collected from the surface.

FIG. 57 is a TD/GC/MS analysis of sample obtained from glass exposed toethyl methylphosphonothioic acid (EMPTA) using the field vacuumextraction device 400. The intact acid was not recovered, but the ethylester O,S-diethyl methylphosphonothioate was detected at ˜11.45 min.

The top trace in FIG. 58 is a total ion chromatogram, acquired from asurface exposed to IMPA. IMPA is another hydrolysis product of GB, andhence represents an important class of CAS compounds. Being a reactivecompound, intact IMPA was not detected in the experiment. However, theisopropyl derivative diisopropyl methylphosphonate (DIMP) was detected.DIMP co-eluted with olefin compounds (RT of about 9.7 min, highlightedby a surrounding box in FIG. 58, top). The olefin compounds eluting atabout 9.7 minutes are expanded in the bottom trace. Specifically, thebottom trace in FIGS. 59A and 59B are single ion chromatograms for m/z71 chromatogram (olefin-derived), for m/z 123 (from DIMP), and for m/z97 (from DIMP).

The mass spectrum of the olefin/paraffin background of FIG. 59A wasclearly not consistent with that of DIMP. However, the deconvolutedspectrum that deconvoluted at retention time of about 9.74 minutes wasexplicitly diagnostic for DIMP (FIG. 59B).

FIG. 60 is a TD/GC/MS analysis of sample obtained from glass exposed toan N-methyl diethanolamine (NMDEA) standard solution using the fieldvacuum extraction device 400. The solid line is the total ionchromatogram and the dashed line is m/z 117 (hypothesized to be fromNMDEA stationary phase conjugates) expanded×100. The GC/MS analysis ofthe NMDEA standard solution did not produce a chromatographic peak witha corresponding mass spectrum that could readily be interpreted in termsof NMDEA. The compound has a molecular weight of 119, but no molecularion at this m/z value or corresponding to the protonated form at m/z 120was observed. The protonated form may eliminate H₂O to form an ion atm/z 102, while the radical cation should eliminate a CH₂OH radical toform m/z 88. No significant fragment ions were observed at these masses.Instead, the chromatogram of the standard solution exhibited a broadpeak with a maximum at about 12 minutes, and tailing off for severalminutes thereafter. FIG. 61 is a mass spectrum that arose from thisbroadened peak, which contained abundant ions at m/z 175, 160, 117 and89. While not wishing to be bound by any particular theory, is thoughtto be reaction of NMDEA with the column stationary phase, which mayexplain the broadened appearance of this peak. The recovery of theconjugate shows that while the detection signature was perturbed by theTD/GC/MS analysis, it was nevertheless indicative of recovery of NMDEA.

In the TD/GC/MS analysis shown in FIG. 60, a normal paraffin-olefinbackground is present, along with the broadened peak that had beenobserved in the analysis of the NMDEA standard solution. The massspectrum shown in FIG. 61 was very similar to that acquired in thestandard analysis, and was characterized by an abundant m/z 117.Plotting the m/z 117 ion chromatogram highlights the broadened elution,and also shows a sharp peak eluting at about 7.05 minutes. This resultis interpreted in terms of the PVE volatilizing and absorbing the NMDEA,after which it is transferred to the GC/MS, where it reacts with thestationary phase as it goes through the column.

FIG. 62 is a TD/GC/MS analysis of glass exposed to an N-ethyldiethanolamine (NEDEA) standard solution obtained using the field vacuumextraction device 400. The GC/MS analysis of the NEDEA standard solutiondisplayed behavior very similar to that seen for the NMDEA analyses,i.e., a sharp chromatographic peak with a mass spectrum thatcorresponded to NEDEA was not generated. The compound has a molecularweight of 133, but no molecular ion at this m/z value or correspondingto the protonated form at m/z 134 was observed. The protonated mayeliminate H₂O to form an ion at m/z 116, while the radical cation shouldeliminate either a CH₃ radical or a CH₂OH radical to form either m/z 118or m/z 102. No significant fragment ions were observed at these masses.Instead, the chromatogram of the standard solution exhibited a broadpeak with maximum at about 11.8 minutes, and tailing off for severalminutes thereafter. FIG. 63 is a mass spectrum that arose from thisbroadened peak contained abundant ions at m/z 189, 174, 130, 117, and89. Ions at m/z 117 and m/z 89 were identical to those for NMDEA, theions at m/z 189 and m/z 174 were also the same, only shifted higher inmass by 14μ, as expected for an ethyl-for-methyl substitution (thedifference between NEDEA and NMDEA). This spectrum has not beenunequivocally interpreted, but is thought to be due to the reaction ofNMDEA with the column stationary phase, which may be consistent with thebroadened appearance of this peak. The TD/GC/MS chromatogram generatedby analysis of the sample obtained using the field vacuum extractiondevice 400 contained a broadened peak with the mass spectrum specifiedabove, only eluting slightly later at about 8.5 minutes. While notwishing to be bound by any particular theory, is thought to be reactionof NEDEA with the column stationary phase, which may explain thebroadened appearance of this peak.

FIG. 64 is a TD/GC/MS analysis of sample obtained from glass exposed topinacolyl methylphosphonic acid (PMPA) standard solution using the fieldvacuum extraction device 400. PMPA is the principal hydrolysis productof soman (GD) and, thus, is important as a CAS compound of interest.PMPA is a moderately strong acid of about pKa˜3.3, which limits itsvolatility and serves to make the compound strongly sorptive to manysurfaces. Thus, it is a difficult compound to recover from theenvironment, and generally does not go through a GC. Analysis of the 10μg/μl standard solution confirmed this expectation, in that no PMPA wasobserved eluting from the column. However, the PMPA contained alow-level impurity, dipinacolyl methylphosphonate (DPMP), which elutedat 16 minutes in the analysis of the standard solution, and wascharacterized by a mass spectrum with abundant ions at m/z 124, 123 and97. These are signature ions for DPMP in the analysis of the PVE sample.The TD/GC/MS analysis of the sample from exposed glass revealed a lowabundance peak eluting at about 11.97 minutes. When the m/z 123signature ion was plotted, which clearly identified this chromatographicpeak as a possibility for DPMP, and the mass spectrum confirmed theassignment. Other peaks in the chromatogram were typical of normalbackground for the field vacuum extraction device 400 and TD/GC/MSsampling and analysis combination.

FIG. 65 is a TD/GC/MS analysis of a sample obtained from glass exposedto a standard solution of triethyl phosphate (TEP) and DIMP using thefield vacuum extraction device 400. The TEP solution was co-spiked withDIMP to evaluate detectability for both compounds in the sameexperiment. FIG. 65 displays prominent peaks for both compounds, DIMPeluting at about 7.0 minutes, and TEP eluting at about 7.6 minutes. TEPand DIMP were detected with high signal-to-noise levels, and hence thefield vacuum extraction device 400 is expected to be able to recover lowconcentrations. In addition, two other phosphoryl compounds weredetected, the first eluting at about 8.32 minutes whose mass spectrumwas consistent with that of an organophosphate derivative. The secondcompound was tri-n-butyl phosphate, eluting at about 12.34 minutes. Thedetection demonstrates the ability of the field vacuum extraction device400 to recover trace impurities from fixed surfaces.

FIG. 66 is a TD/GC/MS analysis of a sample obtained from glass exposedto a standard solution of triethylphosphite (TEPite) and DIMP using thefield vacuum extraction device 400. Analysis of a PVE sample of glassexposed to a standard solution of TEPite did not result in detection ofthe target compound. Instead, the TD/GC/MS chromatogram containedabundant peaks corresponding to diethyl phosphite (DEPite) and dimethylphosphite (DMPite) at retention times of about 7.8 minutes and about 5.1minutes, respectively. In addition, a smaller peak was observed at about6.4 minutes. FIGS. 67A through 67C contain mass spectra of the peaksobserved at about 5.1 minutes, about 6.5 minutes and about 7.8 minutes.The mass spectra are consistent with a phosphoryl compound, and havebeen interpreted as ethyl methyl phosphite. The presence of the methyland ethyl phosphite derivatives suggests that the methanol solvent maybe hydrolyzing the ethoxy groups originally attached to TEPite. It isunlikely that the field vacuum extraction device 400 is causing thechemical modifications. This data indicates the ability of the fieldvacuum extraction device 400 to pick up trace contaminants.

FIG. 68 is a TD/GC/MS analysis of a sample obtained from paintedwallboard exposed to 1,3-propanedithiol (1,3-PDT) standard solutionusing the field vacuum extraction device 400. The top of FIG. 68 is atotal ion chromatograph, which shows abundant 1,2-dithiolane peaks andsignificant siloxane peaks. The bottom of FIG. 68 includes single ionchromatographs; the solid line being m/z 106, the molecular ion for1,2-dithiolane and the dashed line being m/z 108 expanded by twentytimes, the molecular ion for 1,3-PDT. The TD/GC/MS analysis of the PVEsample of wallboard exposed to 1,3-PDT revealed a different envelope ofcompounds in the chemical background, typified by many more siloxanecompounds, as well as olefins, paraffins, and divinyl benzene. Thedominant signal from the standard solution was due to the compoundeluting at about 8.3 minutes, which was assigned as 1,2-dithiolane,based on the mass spectrum. The 1,2-dithiolane compound was asignificant impurity (about 16%) in the standard solution and, thus, wasapplied to the wallboard together with the 1,3-PDT. In addition, 1,3-PDTwas detected, eluting slightly before the 1,2-dithiolane at about 7.5minutes. It was not noticeable in the total ion chromatogram, but wasdistinguished by the single ion chromatogram for m/z 106. The massspectrum generated for this peak was consistent with the compoundassignment. The intensity of the 1,3-PDT chromatographic peak wassignificantly less than expected based on the analysis of the standardsolution. Either the 1,3-PDT was oxidizing in the methanolic solution toproduce the 1,2-dithiolane between the time of the standard analysis andthe wallboard experiment, or the recovery was lower. In fact, recoveryfrom glass suggested that the 1,2-dithiolane should account for about40% of the total (up from 16% in the standard solution analyzed bydirect injection). In the wallboard experiment, 1,2-dithiolane accountsfor on the order of about 95% of the compound applied. Anotherexplanation is that the 1,3-PDT is absorbing into the polymer moreaggressively than is the 1,2-dithiolane, and hence is recovered anddetected much less efficiently.

FIGS. 69A and 69B are TD/GC/MS analyses of a sample obtained frompainted wallboard exposed to diethyl ethylphosphonate (DEEP) standardsolution using the field vacuum extraction device 400. FIG. 69A includesa total ion chromatogram, with DEEP eluting at 10.3 minutes and a singleion chromatograph for m/z 111 (the principal fragment ion in the massspectrum of DEEP), expanded by thirty times. FIG. 69B includes aTD/GC/MS analysis obtained from a sample collected using the fieldvacuum extraction device 400 about seven (7) days after exposure. TheTD/GC/MS analysis samples collected from exposed wallboard samplesshowed that the PVE recovered significant DEEP from the exposedwallboard. DEEP elutes at about 10.3 minutes with a significantchromatographic tail, indicating that the compound is adhering to somepart of the TD/GC/MS system. Wallboard exposed to DEEP was at sampled atdifferent times since exposure (Δt_(exp)) to determine how quickly acompound may deplete after release. To do this, the intensity of the m/z111 ion chromatographic peak (derived from DEEP) was compared atdifferent Δt_(exp) values. Exposed wallboard sampled after Δt_(exp) atabout seven (7) days produced a peak that was about 2.6 times lower thana sample with Δt_(exp) at less than one (1) day. The lower recovery atlonger Δt_(exp) values was due either to diffusion into the bulk andalso to volatilization. The result suggests that the matrix willfunction to preserve the compound, but that for many compounds,depletion is occurring as a function of time. In the DEEP/wallboardexperiment, the depletion rate is estimated at about 0.14 day to aboutone (1) day, based on the depletion seen over the course of about seven(7) days, and assuming single exponential behavior.

FIGS. 70A and 70B are TD/GC/MS analyses of a sample obtained frompainted wallboard exposed to diethyl phosphite (DEPite) standardsolution using the field vacuum extraction device 400. FIG. 70A is atotal ion chromatogram. FIG. 70B is includes single ion chromatograms,expanded one hundred times for m/z 83, m/z 80, and m/z 111. Sampling ofwallboard exposed to the diethylphosphite standard solution resulted ina TD/GC/MS chromatogram that contained the characteristic paraffins,olefins and siloxanes that typify the chemistry of the wallboard. Theonly phosphoryl-derived compound that overtly stands out in the totalion chromatogram corresponds to triethylphosphate at about 10.7 minutes,as indicated by its mass spectrum. Triethylphosphate is an impurity inthe diethylphosphite standard solution. Careful inspection of the singleion chromatograms of m/z 80, m/z 83 and m/z 111 readily reveals thepresence of three phosphite compounds. Both dimethylphosphite and ethylmethylphosphite display a prominent ion at m/z 80, and broadened peaksat about 5.9 minutes and about 7.1 minutes correspond to these twocompounds, as indicated by the mass spectra measured at these retentiontimes. Both of these compounds are derived from diethylphosphite as aresult of hydrolysis and re-esterification with the methanol used as thesolvent in the standard solutions. Diethylphosphite is also recovered bythe PVE, but is identified only with more difficulty. Identification isbased on the elevated baseline seen in both of the ion chromatograms ofm/z 111 and m/z 83, which are diagnostic for diethylphosphite. Theymaximize at about 8.5 minutes. While identification was difficult inthese experiments, it may be simplified by implementation ofchromatography adapted for the alkylphosphites; this may sharpen thebroadly eluting peaks, permitting easier chromatographic assignment andimproved signal-to-noise in the mass spectra.

FIGS. 71A and 71B are TD/GC/MS analyses of samples obtained from paintedwallboard exposed to triethylphosphite (TEPite) standard solution usingthe field vacuum extraction device 400. FIG. 71A is a total ionchromatogram. FIG. 71B includes single ion chromatograms for m/z 79(expanded one hundred times) at m/z 65 (expanded four hundred times),and at m/z 155 (expanded eight hundred times). Four differentphosphoryl-bearing compounds were collected using the field vacuumextraction device 400 on wallboard that was exposed to TEPite. None ofthe compounds were intact TEPite, but all were derived from it.Dimethylphosphite eluted at about 5.7 minutes and appeared as abroadened, tailing peak in the m/z 79 ion chromatogram (FIG. 71B). Ethylmethylphosphite displayed the same profile but eluted at 7.5 min in them/z 79 chromatogram, which appears as a prominent fragment ion in themass spectra of both compounds. Diethyl phosphite is also observed,eluting at about 8.5 minutes, with the same broadened profile. It is notdefined by a unique single ion, but the compound may be identified byexamining the chromatographic profiles of m/z 65, m/z 83 and m/z 111,which are all prominent in the mass spectrum of diethylphosphite. Theelution behavior is illustrated by FIG. 71B; the spikes on the top ofthe broad peak are derived from co-eluting paraffins and siloxanes nearthis retention time. The fourth phosphoryl compound wastriethylphosphate, which elutes at about 10.9 minutes. It cannot beobserved in the total ion chromatogram, but is clearly seen in the m/z155 ion chromatogram (FIG. 71B). As in the case of the phosphites, thecompound is clearly recovered. Triethylphosphate is probably formed fromoxidation of the TEPite, which is not present in the standard solution.Instead, it may react with either by hydrolysis, methanolysis, or byoxidation.

FIG. 72 is a TD/GC/MS analysis of a sample obtained from paintedwallboard exposed to ethyl dichlorothiophosphate (EDCTP) standardsolution. The analysis shows both a total ion chromatogram and a singleion chromatogram for m/z 61, expanded eight hundred times. Sampling ofwallboard exposed to the EDCTP standard solution resulted in recovery ofthe methanolysis product O,O′,O″-dimethyl, ethylthiophosphate eluting atabout 9.3 minutes. Intact chlorothiophosphate derivatives did notsurvive the environment on the wallboard. While not wishing to be boundby any particular theory, the chloro derivatives may have undergonehydrolysis, forming O-ethylthiophosphoric acid, which strongly bound tosurface reactive moieties. Another low abundance thiophosphate eluted atabout 11.5 minutes, and had a mass spectrum consistent withO,O′-dimethyl,S-ethylthiophosphate. This compound was not observed inthe analyses of the standard, and represents recovery of a very traceimpurity by the field vacuum extraction device 400. The EDCTP standardsolution also contained low levels of sulfides that were readilydetected. Diethyldisulfide and diethyltrisulfide eluted at about 7.1minutes and about 10.9 minutes, respectively. These compounds werereadily identified on the basis of their mass spectra.

In the examples described herein, the primary CAS compound wasrecovered. Normal applications were in the microgram range; however, theresponse of the TD/GC/MS was generally greater than about 10⁷ counts.These robust analytical responses show that the field vacuum extractiondevice 400 may be used to recover quantities of chemical compounds inthe low nanogram range, a conclusion supported by the detection ofimpurities and hydrolysis products.

The envelope of test compounds spanned a range of phosphoryl, sulfide,alcohol, and amine functional groups, which represent the majority ofthe chemistry that may be encountered in a CAS collection. With only afew exceptions, the compounds were efficiently recovered, whichindicates that the field vacuum extraction device 400 may be effectivefor a broad range of chemical compounds.

Impurities and hydrolysis products collected using the field vacuumextraction device 400 shown in the examples described herein areindicative of compounds representative of impurities that may accompanya CWA release, and may constitute the CAS compounds that are desiredwhen sampling fixed surfaces using the field vacuum extraction device400. The impurities were present only at very low levels, withfractional abundances of perhaps less than or equal to 0.001, and yetwere still readily recovered by the PVE suggesting that low nanogramquantities are recoverable.

Thus, the field vacuum extraction device 400 has been shown to beeffective for collecting several classes of target compounds, includingsulfides, amines, phosphines, phosphates, and phosphonates. Theseexamples demonstrate that the field vacuum extraction device 400 iscapable of collecting organic compounds as well as hydrolysis productsindicative of chemistry occurring on the surfaces between the organiccompounds and indigenous compounds in the surface environment. Theefficacy of the field vacuum extraction device 400 is demonstrated bythe experiments described herein, combined with the fact that the fieldvacuum extraction device 400 may be fabricated from off-the-shelfcomponents and its operational simplicity. The device is small,inexpensive, easy-to-operate and effective for non-destructive samplingfrom fixed surfaces. The samples produced, viz., exposed SPME fibers,are amenable to analysis in a large number of laboratories, and, inaddition, the syringe barrel and plunger seal are disposable, therebyeliminating carryover concerns. Additionally, the recovered samplessorbed onto the SPME fibers may be stored for transport to laboratoriesor archival purposes.

The invention has been described herein in language more or lessspecific as to structural and methodical features. It is to beunderstood, however, that the invention is not limited to the specificfeatures shown and described, since the means herein disclosed comprisepreferred forms of putting the invention into effect. The invention is,therefore, claimed in any of its forms or modifications within theproper scope of the appended claims appropriately interpreted inaccordance with the doctrine of equivalents.

1. A device for extracting at least one chemical compound from asurface, comprising: a chamber; a plunger slidably received in thechamber from one end thereof and having an aperture therethrough, theaperture sealed by a perforable material; a peripheral sealing elementat an opposing end of the chamber configured to seal against a surfacefor preventing fluid from entering the chamber upon retraction of theplunger; and at least one pressure sensor for determining a pressurewithin the chamber.
 2. The device of claim 1, wherein the plungercomprises a portion sized for sealing engagement with a wall of thechamber.
 3. The device of claim 1, further comprising a sorbent materialsized and configured to be inserted through the aperture in the plunger.4. The device of claim 2, wherein the at least one pressure sensor iscommunicable with an interior of the chamber through an opening in awall thereof.
 5. The device of claim 1, wherein at least one pressuresensor comprises at least one of a pressure sensitive pigment and apressure sensitive paint.
 6. The device of claim 4, wherein the at leastone of a pressure sensitive pigment and a pressure sensitive paint aredisposed within a void in a wall of the chamber.
 7. A device forextracting at least one chemical compound from a surface, comprising: achamber; a plunger having an aperture therethrough, slidably insertedinto the chamber from an end thereof, the plunger having a portion sizedfor sealing engagement within the chamber; a sorbent material sized andconfigured to be inserted through the aperture in the plunger; aperipheral face seal for contacting a surface proximate an end of thechamber opposite the plunger and preventing fluid from entering thechamber upon retraction of the plunger; and at least one actuationdevice operably coupled to the plunger and configured for moving theplunger within the chamber.
 8. The device of claim 7, wherein the atleast actuation device comprises at least one of a drill device, alinear actuator and a worm gear.
 9. The device of claim 8, wherein thedrill device comprises a swivel joint attached to the plunger.
 10. Thedevice of claim 8, wherein the linear actuator comprises a rack andpinion, the rack being attached to the plunger.
 11. The device of claim7, wherein the at least one actuation device comprises: an assist barrelencompassing the chamber; a mating disc attaching the assist barrel tothe plunger; a compressed spring attached to a base of the chamber at afirst end and to the assist barrel at a second end, opposite end; and alatch configured for releasing the compressed spring.
 12. The device ofclaim 7, further comprising a container configured for holding a sampleand aligning with a seal overlying a base of the chamber.
 13. A devicefor extracting at least one chemical compound from a surface,comprising: a chamber having a plunger slidably inserted from one endthereof, the plunger slidably, sealingly fitted within the chamber andhaving an aperture therethrough; a sorbent material sized and configuredto be inserted through the aperture in the plunger; a seal adjacent aperipheral wall of the chamber at another end thereof for preventingfluid from entering the chamber upon retraction of the plunger uponcontact of the seal with a surface; and at least one heating elementconfigured and located for heating the chamber.
 14. The device of claim13, wherein the at least one heating element comprises a thermitematerial disposed in an envelope.
 15. The device of claim 13, whereinthe at least one heating element is disposed around a portion of thechamber.
 16. The device of claim 13, wherein the at least one heatingelement is configured to increase a temperature within the chamber by atleast 10° C.
 17. The device of claim 13, further comprising a containerconfigured for holding a sample and aligning with a seal overlying abase of the chamber.